Fieldcage

[MiryamMV]

This PR completes the NEXT100 Field Cage according to the up-to-date detector drawings. It adds the copper rings, the ring holders, the cathode ring and other minor changes.

[MiryamMV]

Here is a document with all the measurements provided by Sara . (Some may change in the code) fieldcage_measurements_medidas.pdf

[gondiaz]

Cosmetic revision:

• Use nexus conventions nexus-coding-conventions. There are plenty of lines exceeding the 80-100 character convention.
• Indent lines 206-208. Besides, I think it is clearer if you define el_gap_zpos_ = GetELzCoord() - el_gap_length_/2..
• Be consistent with vertical spacings. For example, set a fixed 2 line spacing between methods. Also, remove at least one of the lines between 667-669.
• Be consistent with horizontal spacings. For example, look the definitions at lines 329 and 342. I would prefer the 342 indentation since it is how is mostly used in nexus.
• Remove right slashed in line 627.
• Remove commented lines 707 and 708.

[gondiaz]

PE100 holders surrounding the cathode are not implemented. I would add them also.

[MiryamMV]

Here we have a list of magnitudes that are still to confirm:

• position of the cathode grid in the cathode ring.
• simulation of the photoetched grids.
• gate-TP distance
• gate-teflon panels distance
• gate/anode internal and external diameters
• gate_ring thickness
• cathode, anode and gate transparency

[gondiaz]

This PR reviews the Next100 field cage elements, their positions and sides. There are still some parameters that must be reviewed as soon as the final design is provided by technicians. Particularly important is the gate-to-tracking-plane distance, still not confirmed. The implementation is complete and accurate, therefore I approve it. Great work!